On densely populated circuit boards, space consumption is a critical issue. Each additional component placed on a circuit board takes up additional surface area. For example, if more capacitance is required for a given application, additional capacitors must be added to the circuit board, taking up additional surface area. With manufacturers trying to fit more and more components on circuit boards, techniques which minimize the amount of surface area of given components are sought after. This applies to capacitors as much as other components.
At the same time, manufacturers are constantly looking for ways to reduce overall circuit board surface area. Stacking is one technique that has been utilized to conserve surface area. One such stacking technique stacks integrated circuits on top of one another. In U.S. Pat. No. 6,576,992 B1 (the '992 patent), owned by assignee of the present application and incorporated herein by reference, integrated circuits are stacked in chip-scale packages (“CSPs”) into modules. Flex circuits are used to connect a pair of CSPs, conserving board surface area at the expense of added component height. This is a trade-off that manufacturers are often willing to make to allow smaller circuit boards.